package common;

import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DBUtil {
    private static final String URL="jdbc:mysql://127.0.0.1:3306/oj_database?serverTimezone=GMT&allowPublicKeyRetrieval=true&useSSL=false&characterEncoding=utf8";
    private static final String USERNAME="root";
    private static final String PASSWORD="";

    private static volatile DataSource dataSource=null;

    private static DataSource getDataSource(){
        if(dataSource==null){
            synchronized (DBUtil.class){
                if(dataSource==null){
                    MysqlDataSource mysqlDataSource=new MysqlDataSource();
                    mysqlDataSource.setURL(URL);
                    mysqlDataSource.setUser(USERNAME);
                    mysqlDataSource.setPassword(PASSWORD);
                    dataSource=mysqlDataSource;
                }
            }
        }
        return dataSource;
    }

    public static Connection getConnection() {
        try {
            return getDataSource().getConnection();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static void close(Connection connection, PreparedStatement statement, ResultSet resultSet){
        if(resultSet!=null){
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(connection!=null){
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}
